The US and Ukraine organized a Sea Breeze rehearsal with the participation of more than 30 countries on the Black Sea, the Russian army said being closely monitored.

The Sea Breeze 2012 Naval rehearsal launches today and will last two weeks in Southern Ukrainian territory and part of the Black Sea, with the presence of 30 warships, 40 aircraft and about 4,000 soldiers from Ukraine,

The rehearsal helps improve the possibility of communion between the air force, navy and the army of participating countries.

USS Ross destroyer at Odessa Harbor on June 27.

Colonel Kyle Gantt, a US Navy spokesman, said the large number of participating countries reflecting the common commitment to ensure free access to international waters.

The Russian Defense Ministry announced it was monitoring the activities of international ships participating in the exercise.

Activities take place in the context of escalating stress between NATO and Russia on the Black Sea.

Sea Breeze is an annual naval exercise held by NATO on the Black Sea since 1997. Last year's event has the participation of more than 20 battleships, many aircraft with about 2,000 soldiers in Ukraine, USA, Bugaria, Georgia

NATO continuously expanded to the East with exercises and things to kill the Russian border since 2014, in the context of deteriorating bilateral relations.